The substantial size of some hydroelectric projects and the extensive total surface area covered by reservoirs globally require that research determining the impacts of these developments be done at ever-increasing spatial and temporal scales. As a consequence of this research, new views are emerging about the spatial extent and longevity of the environmental and social impacts of such developments. New findings challenge the notion of hydroelectric development as a benign alternative to other forms of power generation. This review examines the intertwined environmental and social effects of methylmercury bioaccumulation in the food web, emission of greenhouse gases from reservoirs, downstream effects of altered flows, and impacts on biodiversity, each of which operates at its own unique spatial and temporal scales. Methylmercury bioaccumulation occurs at the smallest spatial and temporal scales of the four impacts reviewed, whereas downstream effects usually occur at the largest scales. Greenhouse gas emissions, the newest surprise connected with large-scale hydroelectric development, are relatively short term but eventually may have important global-scale consequences. Limitation of biodiversity by hydroelectric development usually occurs at intermediate spatial and temporal scales. Knowledge developed from working at expanded spatial and temporal scales should be an important part of future decision making for large-scale hydroelectric development.
Our objective was to study the effects of experimental flooding of a small wetland lake on the methyl mercury (MeHg) concentrations in aquatic insects and to compare MeHg concentrations in insects with those in water and fish from the same system. Insects were collected from the shorelines of the experimental reservoir before and after flooding, an undisturbed wetland lake, and an oligotrophic lake, all in the Experimental Lakes Area in northwestern Ontario. Samples were identified to the lowest possible taxon and categorized into functional feeding groups (FFGs; predators or collector/shredders). The insects were analyzed for MeHg and total Hg using clean techniques. Contamination was not a problem because levels of MeHg in insects were much higher than background concentrations. Odonata, Corixidae, Gerridae, Gyrinidae, and Phryganeidae/Polycentropodidae exhibited increases in MeHg concentrations in response to flooding. When data were grouped into FFGs, increases were observed in predators. There were insufficient numbers of collector/shredders collected to make a definitive conclusion on MeHg increases. Predators exhibited an approximately threefold increase in MeHg concentrations after flooding compared with a 20-fold increase in water concentrations and a four- to five-fold increase in fish concentrations. Trends in MeHg concentrations in aquatic insects from reservoirs and natural lakes in Finland and northern Québec were similar to ours. Evidence of an increase in MeHg concentrations in the lower food web helps explain increases in MeHg concentrations in fish from reservoirs because food is the major pathway of MeHg uptake in fish tissue.
Arsenic concentrations were measured in aquatic invertebrates, macrophytes, sediments, and water of lakes in the vicinity of Yellowknife (N.W.T.), Canada. In arsenic-contaminated lakes the arsenic concentration ranged from 0.70 to 5.5 ppm in water, 6 to 3,500 ppm in bottom sediments, 150 to 3,700 ppm in macrophytes, 700 to 2,400 ppm in zooplankton, and less than 1 to 1,300 ppm in other invertebrates. The arsenic concentration in invertebrates varied with sampling time, place, and taxon. Arsenic concentration factors were calculated, and found to decrease with increasing concentration of arsenic in ecosystem components of the lake. No evidence was found for biomagnification of arsenic through ascending trophic levels. In high-arsenic lakes herbivores had the highest arsenic concentrations, and omnivores the lowest. Pelecypoda, Ephemeroptera, Amphipoda, and Hirudinea were conspicuously absent from high-arsenic lakes. These particular organisms may be more susceptible to the effects of arsenic than others.
BackgroundPulmonary arterial hypertension (PAH) is a severe complication of systemic sclerosis (SSc).ObjectivesIn this longitudinal study we aimed to identify factors associated with an unfavourable outcome in SSc patients with early PAH (SSc-PAH) from the DETECT cohort.MethodsDETECT enrolled patients with SSc fulfilling the 1980 ACR classification criteria, with a minimal disease duration of 3 years since the first non-Raynaud symptom, and with a lung diffusion capacity for CO (DLCO) <60% of the predicted value. A broad range of clinical and laboratory parameters potentially associated with PAH were assessed, and right heart catheterisation (RHC) was performed in all patients at baseline. Patients diagnosed with PAH were followed up for up to 3 years in centers that agreed for the longitudinal part of the DETECT study, collecting data on survival, World Health Organization (WHO) Functional Class (FC), hospitalization, and PAH-specific treatment. Disease progression was defined as the occurrence of any of the following: WHO-FC worsening, PAH therapy with a drug combination, hospitalization, or death. Associations between baseline variables and disease progression were assessed by univariable logistic regression.ResultsOf the 145 SSc patients with PH enrolled in DETECT, 87 patients were diagnosed with PAH, of whom 57 participated in the longitudinal study (median follow-up time 12.6 months, interquartile range 10.7–21.7 months). Among these 57 patients, 33/57 (57.9%) had mild PAH, in WHO FC I or II. During follow-up, 25/57 (43.9%) patients had disease progression (4 deaths, 11 hospitalizations for PAH, 14 with worsening in WHO FC, and 8 received PAH-specific combination treatment), with a 1-year survival rate of 93%. The following factors [odds ratio, (95% confidence interval)] were associated with disease progression: male gender [4.1 (1.2–14.1)], high Forced Vital Capacity (FVC) % predicted/ DLCO % predicted ratio [3.6 (1.2–10.7)], and high Borg dyspnoea index [1.7 (1.1–2.6)]. Low DLCO (% predicted) was also significantly associated with progression [area under the curve (95% CI) 0.8 (0.6–0.9)], but the relationship was not linear.ConclusionsMore than 40% of early-diagnosed SSc-PAH patients in the DETECT cohort who were followed over time had disease progression during a rather short follow-up time, with male gender, functional capacity, and pulmonary function tests (low DLCO, high FVC%/DLCO % predicted ratio) at PAH diagnosis being associated with progression. This suggests that even mild and early detected PAH should be regarded as a high-risk complication of SSc, and every effort to make an early diagnosis is valuable.AcknowledgementsThe authors thank all investigators and patients involved in DETECT.Disclosure of InterestC. Mihai Grant/research support from: Actelion, Geneva Romfarm, Abbvie, Speakers bureau: Actelion, Geneva-Romfarm, Roche-Genentech, M. Antic: None declared, R. Dobrota Grant/research support from: Pfizer, Actelion, Speakers bureau: Actelion, D. Bondermann Consultant for: Actelion, GSK, MSD, B...
Because Milton believed language to be an external manifestation of inner spirit, he exposes his political and religious adversaries’ corruptions of style by impersonating them. By parodying their linguistic abuses, he supports his assertions about their dishonesty and ignorance. His verbal range is broad and various, shifting from mockery of High-Church grandiloquence, to burlesque of commercial jargon, to rough satire. He uses his own plain, concrete diction, however, as a moral and stylistic norm. Ridicule of Bishop Hall's peculiar diction and aphoristic phrasing plays an important part in Animadversions and An Apology. Through parody, Milton awakens his readers’ perceptions, persuading them to participate with him in the controversy over church reform and religious liberty.
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